| Summary: |
The proposed research project aims at studying the endurance durability of geosynthetics.<
The application of geosynthetics in civil engineering works has been increasing, thus the questions regarding their durability, as well as the definition of reduction factors to use in their design are becoming more and more relevant. In Portugal, although it started some decades ago, the application of geosynthetics it is done, in many cases, in an unsupported technically way. Internationally the work done is not much extended, reflected on a assumed lack of well documented experience , which is due to the large number of parameters that influence this problem, resulting from the combination and interaction of numerous parameters present in the soil environment.
Refers 2 groups of items associated with the durability of geosynthetics: 1) related to the endurance of the materials, and include damage during installation (DDI), creep, stress relaxation, abrasion and compressive creep; and 2) related to the degradation, and include oxidation, UV radiation, hydrolysis and chemical and biological agents.
Each group includes several agents and mechanisms that play an important role on the durability of geosynthetics. Therefore, it is necessary to know and to identify the main parameters that condition each one of them and how this is reflected on the functional properties of the geosynthetics. Traditionally the study of the endurance durability of geosynthetics refers mainly to the application of these materials as reinforcements, where the tensile mechanical properties are the relevant functional properties. Nevertheless, there are many other applications where these questions are equally relevant and that have been less studied internationally. Therefore, the proposed research project aims also at studying the effect of the endurance agents and mechanisms under well controlled conditions, considering a limited and coherent set of parameters, on both mechanical and hydraulic  |
Summary
The proposed research project aims at studying the endurance durability of geosynthetics.<
The application of geosynthetics in civil engineering works has been increasing, thus the questions regarding their durability, as well as the definition of reduction factors to use in their design are becoming more and more relevant. In Portugal, although it started some decades ago, the application of geosynthetics it is done, in many cases, in an unsupported technically way. Internationally the work done is not much extended, reflected on a assumed lack of well documented experience , which is due to the large number of parameters that influence this problem, resulting from the combination and interaction of numerous parameters present in the soil environment.
Refers 2 groups of items associated with the durability of geosynthetics: 1) related to the endurance of the materials, and include damage during installation (DDI), creep, stress relaxation, abrasion and compressive creep; and 2) related to the degradation, and include oxidation, UV radiation, hydrolysis and chemical and biological agents.
Each group includes several agents and mechanisms that play an important role on the durability of geosynthetics. Therefore, it is necessary to know and to identify the main parameters that condition each one of them and how this is reflected on the functional properties of the geosynthetics. Traditionally the study of the endurance durability of geosynthetics refers mainly to the application of these materials as reinforcements, where the tensile mechanical properties are the relevant functional properties. Nevertheless, there are many other applications where these questions are equally relevant and that have been less studied internationally. Therefore, the proposed research project aims also at studying the effect of the endurance agents and mechanisms under well controlled conditions, considering a limited and coherent set of parameters, on both mechanical and hydraulic properties of geosynthetics. This way, functions of geosynthetics other than reinforcement, such as filtration, drainage and separation, will also be studied.
Thus, the proposed research project will address the following issues: 1) select appropriate geosynthetics; 2) submit geosynthetics to endurance durability related agents and mechanisms acting isolated; 3) study the synergy between agents by submitting geosynthetics to 2 or more relevant agents and mechanisms; 4) evaluate the changes on functional properties of geosynthetics; 5) propose values for reduction factors to use in the design of such geosynthetics to consider the effect of the agents and mechanisms considered on their relevant functional properties.
The team has large experience in studying such items, having researched several questions related to the durability of geosynthetics, for both endurance and degradation issues, were studied and some prototype equipments were developed.
The proposed research project has a significantly extended volume of new work, both nationally and internationally. In fact, as the study of such questions requires time and the superposition of the effects of different agents and mechanisms is long and can be difficult to carry out (if to ambitious), there is no published work similar to the one here proposed.
Therefore, besides the publications resulting directly from the proposed work, it is aimed to create a database of reduction factors to be used in the design of geosynthetics to consider the issues of endurance durability and that can be used by designers, in order to allow more realistic and economic designs, widening the successful use of the geosynthetics and make the most of the environmental advantages associated with their use. |